This invention relates to circuits, for example, a circuit to provide short-circuit protection for a field effect transistor.
There are numerous applications in electrical systems where short-circuit protection for a power device is desired. For instance, if a load coupled to the power device is inadvertently shorted, the power device will conduct an excessive current at an elevated voltage which typically results in destruction of the power device.
At least one attempt to provide short-circuit protection for a power device includes sensing the current through the power device by monitoring the voltage across a sense resistor which is coupled in series with the power device. When the current through the power device reaches a predetermined level, the voltage across the sense resistor turns on a bipolar transistor thereby reducing the drive to the power device. However, this attempt dissipates a large amount of power and possesses a high on-resistance.
Another attempt at providing short-circuit protection for a power device includes monitoring the temperature of the die of which the power device is fabricated on. In this attempt, the power device is turned off when the temperature of the die exceeds a predetermined limit. However, if destruction to the power device occurs before the temperature exceeds the predetermined limit, this attempt becomes futile.
Hence, there exists a need for an improved circuit to provide short-circuit protection for a power device.